If you turn on WP_DEBUG, you may find an error like this:
Deprecated: Function create_function() is deprecated in /wp-content/themes/your-theme/functions/widgets/widget-categories.php on line 106To fix, change this:
add_action( 'widgets_init', create_function( '', 'return register_widget("Woo_Widget_AdSpace");' ), 1 );to this:
add_action ( 'widgets_init', 'Woo_Widget_init_AdSpace' ); function Woo_Widget_init_AdSpace() { return register_widget('Woo_Widget_AdSpace'); }More info here: https://wordpress.org/support/topic/function-create_function-is-deprecated-in-php-7-2-0/ Warning: Please note that if your plugin or theme is by a third-party who has updates, any updates will remove your fixes. Please notify the plugin author or theme author rather than making these changes yourself.